Processes for continuous direct chill casting of aluminum alloys, including aluminum-lithium alloys, are known in the prior art. For example, Moritz U.S. Pat. No. 3,212,142 discloses a process and apparatus for continuous aluminum casting. The apparatus includes a mold having an outer metal shell lined with an annular header or liner of insulating material. The insulating header is made from a composition wherein asbestos fibers are distributed in an inorganic binder.
Asbestos-containing headers have performed satisfactorily in the aluminum industry for many years. However, in recent times, it has become necessary to discontinue usage of asbestos-containing materials because of health concerns. Accordingly, there is presently a need for asbestos-free headers giving aluminum casting performance comparable to headers in which asbestos is present.
It is a principal object of the present invention to provide an aluminum casting process utilizing a mold having a header wherein asbestos is replaced by a suitable substitute material.
A related objective of the invention is to provide a process for casting aluminum-lithium alloys utilizing a header that is resistant to attack by the molten metal.
Additional objectives and advantages of the invention will become readily apparent to persons skilled in the art from the following detailed description of our invention.